traversed by the Bio Negro; the Bald-headed Ouakari appears
to be confined to the triangle formed by the union of the
Amazon with another affluent, the Japura; and the Hed Ouakari
to the forests on the north bank of the Amazon opposite Olivenga,
and lying between the main stream and the River Iga. Each of
them evidently takes the place of the others in its particular
district. Of this peculiar kind of distribution few instances are
known amongst mammals, but many somewhat similar cases have
been observed In birds, reptiles, and insects."
The genus Pithecia, the Sakis, consists of five species with
long bushy tails, which are non-prehensile. They are bearded
and have a thumb. Like the last genus, Pithecia does not
extend into Central America. The incisors project forwards, and
the lower jaw Is deep, though the howling apparatus of Mycetes
is wanting. The thin, closely-set, and projecting incisors are very
suggestive of those of the Lemurs. BracJiyurus Is much like
Pithecia in this respect, and both differ markedly from such a
genus as Gebus, where the lower Incisors are vertical. An
anatomical peculiarity of Pithecia, is the breadth of the ribs.
P. satanas is perhaps the best-known species, but all five have
been exhibited at the Zoological Society's Gardens. As Its
name suggests, P. satanas Is entirely black; it shows a curious
point of difference from P. cfieiropotes in its way of drinking.
The latter species, as Its name denotes, uses its hand to drink,
while P. satanas puts Its mouth to the water. P. albincLsa, is
black with a red patch on the nose, within which again is a
small white patch.
GROUP II. CATARMHINA.
The Catarrhine Apes are divisible into three or perhaps only
two families, the Cercopithecidae and the Simiidae, to which
must be added the Hominidae. The Simiidae are sometimes
spoken of as the Anthropoid Apes.
Fam. 1. Cercopithecidae.—Of the Cercopithecidae there are
eight genera (perhaps nine) to be recognised, which may be dis-
tributed Into two sub-families. The first of these two sub-families,
that of the Cercopittiecinae, has the following characters :—There
BT& cheek pouches in which the animals store food temporarily.